GB2069725A

GB2069725A - Level regulator for an automotive vehicle

Info

Publication number: GB2069725A
Application number: GB8101353A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1980-01-16
Filing date: 1981-01-16
Publication date: 1981-08-26
Also published as: DE3101122A1; GB2069725B; FR2477987A1; US4382603A; JPS5699809A

Description

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GB 2 069 725 A

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SPECIFICATION

Level regulator for an automotive vehicle

5 Background of the invention

1. Field of the invention

The present invention relates generally to a level regulator for an automotive vehicle and more particularly to a level regulator provided with a mecha-10 nical switch sensor to turn off the supply voltage applied to the amplifiers while the level regulator is * not in operation.

2. Description of the prior art

15 As is well known, there exists a level regulator for an automotive vehicle which can automatically regulate or correct the level or height of the vehicle. This level regulator is operated when the level of the vehicle is too low because passengers or freight 20 have been loaded into the vehicle, or too high because they have been unloaded therefrom.

In the prior-art level regulator, however, since the supply voltage is applied to the regulator only when the ignition switch is kept turned on, there has been 25 a problem in that it is impossible to regulate the level of the vehicle when the ignition switch is turned off such as when the vehicle is left parked on a slope. Therefore, in this case, when the ignition switch is turned off with the vehicle full loaded with passen-30 gers orfreight, although it is possible to maintain the level as it is with the vehicle full loaded, the level of the vehicle is necessarily increased after the vehicle has been unloaded.

On the other hand, although it is possible to apply 35 the supply voltage to the regulator directly from the battery without providing an ignition switch therebetween, since the supply voltage is always applied thereto even when no level regulation is being performed, a dark current inevitably continues to 40 flow, so that the battery is discharged. A more detailed description of the prior-art level regulator will be made hereinafter with reference to Figure 1.

Summary of the invention 45 With these problems in mind therefore, it is the primary object of the present invention to provide a ilevel regulator for an automotive vehicle which can apply the supply voltage to the amplifiers only when the mechanical switches of the level sensors are kept 50 .turned on, that is when the level regulator is in operation.

To achieve the above-mentioned object, the level regulator of the present invention comprises two level sensors of mechanical switches, which can 55 additionally function as a switching means to apply the supply voltage to the amplifiers when turned on and to cut off the supply voltage from the battery when turned off.

Therefore, the level regulator of the present inven-60 tion can regulate the vehicle level at any time when necessary, regardless of the on/off position of the ignition switch, and can also prevent the battery from discharging wastefully and excessively.

65 Brief description of the drawings

The features and advantages of the level regulator according to the present invention will be more clearly appreciated from the following description taken in conjunction with the accompanying draw-70 ings in which like reference numerals designate corresponding elements and in which:

Figure 1 is a schematic wiring block diagram of a prior-art level regulator for an automotive vehicle; Figure 2 is a schematic wiring block diagram of a 75 first embodiment of the level regulator of the present invention; and

Figure 3 is a wiring diagram of a second embodiment of the level regulator of the present invention.

80 Detailed description of the preferred embodiments To facilitate understanding of the present invention, a brief reference will be made to a prior-art level regulator for an automotive vehicle. Referring to Figure 1, after an ignition switch 1 has been turned 85 on, a level-up signal S-tis outputted from a level-up sensor 2 when the level of the vehicle is too low because passengers orfreight have been loaded into the vehicle, and next this signal S, is amplified through a level-up amplifier 3 into an UP-signal. This 90 UP-signal energizes a compression solenoid valve 5 for injecting a gas into a shock absorber 6 to increase the level of the vehicle. When the level has been adjusted to a predetermined value, since the level-up signal Si is no longer outputted from the level-up 95 sensor 2, the compression solenoid valve 5 is closed to maintain the level.

On the other hand, a level-down signal S2 is outputted from a level-down sensor 7 when the level of the vehicle 13 is too high because passengers or 100 freight have been unloaded from the vehicle, and next this signal S2 is amplified through a level-down amplifier 8 into a DN-signal. This DIM-signal energizes an exhaust solenoid valve 9 for exhausting the gas from the shock absorber 6 to decrease the level 105 of the vehicle. When the level has been adjusted to a predetermined value, since the level-down signal S2 is no longer outputted from the level-down sensor 7, the exhaust solenoid valve 9 is closed to maintain the level. In this case, the compression solenoid 110 valve 5, the exhaust solenoid valve 9, and the shock absorber 6 together are termed a level regulating means 4.

In the prior-art level regulator described above with reference to Figure 1, since the level regulator is 115 so designed that the supply voltage is applied thereto only while the ignition switch 1 is kept turned on, it is impossible to regulate the level when the ignition switch is kept turned off, even if the level varies.

120 Therefore, in the case when the vehicle is fully loaded with passengers orfreight, if the compression solenoid valve 5 and the exhaust solenoid valve 9 are of the normally-closed type of valve, the level can be maintained as it is without changing the level 125 even if the ignition switch 1 is turned off; however, the level is inevitably increased after passengers or freight have been unloaded therefrom.

As a measure to cope with this problem, there exists a level regulator for an automotive vehicle in 130 which the supply voltage is always applied thereto

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directly from the battery regardless of the on/off position of the ignition switch; however, in this case a dark current is always flowing therefrom even when no level regulation is being performed and 5 therefore the battery can easily be discharged waste-fully. This may cause the battery 10 to be excessively discharged and there has been a problem that it could be difficult to start the engine.

In view of the above description, reference is now 10 made to Figures 2 and 3, and more specifically to Figure 2, wherein an embodiment of the level regulator of the present invention is illustrated.

In Figure 2, the level-up sensor 2 and the level-down sensor 7 are mechanical switching means 15 such as a microswitch 11 or 12, which are automatically turned on or off in accordance with the up- or down-motion of a mechanical means (not shown) when the level of the vehicle is below or above a predetermined value.

20 The level sensor switches 2 and 7 detect the level of the vehicle and apply a level-up signal St or a level-down signal S2 to a level-up amplifier 3 or a level-down amplifier 8, respectively.

In addition to the above function, the level sensor 25 switches 2 and 7 apply a supply voltage from a battery 10 to the level-up amplifier 3 and the level-down amplifier 8, respectively, the moment they are kept turned on. In other words, these sensor switches 2 and 7 serve to detect the level and also to 30 apply a voltage to the amplifiers 3 and 8.

Next, a detailed description will be made of the operation of the embodiment shown in Figure 2. When the vehicle level is normal, since the level sensors 2 and 7 are kept turned off, no supply 35 voltage is applied to the amplifiers 3 and 8 from the battery 10, thus allowing saving of power consumption caused by a dark current flowing therethrough.

When the level of the vehicle becomes lower because passengers orfreight are loaded thereinto, 40 the level sensor 2 is turned on; a supply voltage is applied to the amplifier 3 through the switch 11 of the sensor 2; at the same time, the level-up signal Si is inputted to the amplifier 3; the signal St is amplified by the amplifier 3 to obtain an UP-signal. 45 This signal actuates a compression solenoid valve 5 to inject a gas into a shock absorber 6, thereby increasing the level of the vehicle.

When the level is restored to a predetermined value, since no level-up signal St is outputted from 50 the level sensor 2, no UP-signal is outputted from the amplifier 3 and the compression solenoid 5 is closed, maintaining the level of the vehicle.

On the other hand, when the level of the vehicle becomes higher because passengers or freight are 55 unloaded therefrom, the level sensor 7 is turned on; a supply voltage is applied to the amplifier 8 through the switch 12 ofthe sensor7; at the same time, the level-down signal S2 is inputted to the amplifier 8; the signal S2 is amplified by the amplifier 8 to obtain 60 a DN signal. This signal actuates an exhaust solenoid valve 9 to exhaust the gas from the shock absorber 6, thereby decreasing the level ofthe vehicle.

When the level is restored to a predetermined value, since no level-down signal S2 is outputted 65 from the level sensor 7, no DN signal is outputted from the amplifier 9 and the exhaust solenoid 9 is closed, maintaining the level ofthe vehicle.

As described-above, according to the present invention; since the level regulation is performed 70 with the supply voltage only being applied to the amplifiers only when the vehicle level must be regulated, it is possible to make an economical automatic level regulation.

With reference to Figure 3, a second embodiment 75 ofthe present invention will be described herein-below.

In this embodiment, a power supply controller 17 is additionally provided and the level-up sensor 2 and the level-down sensor 7 use mechanical switch-80 ing means such as a reed switch 15 or 16, enclosed-by a glass case, which are automatically turned on or off magnetically from the outside ofthe glass case (because the reeds are made of a magnetic material) in accordance with the up-and down-motion of a 85 magnetic means (not shown) when the level ofthe vehicle is below or above a predetermined value. In this embodiment, it is, of course, possible to turn on or off the reed switches electromagneticallyfrom outside the glass case.

90 When either of the reed switches 15 and 16 is turned on, either ofthe level signals St and S2 is generated and is applied to the base of a transistor Tr1 through either ofthe diodes Di or D2 and a resistor Rt to turn on the transistor Tr1. In this 95 embodiment, since a condenser Ci is connected between the base of the transistor Tr1 and ground, the transistor Tr1 is not turned on the moment the level signal Si is applied thereto. However, when the base voltage rises gradually and exceeds a fixed 100 potential (the threshold voltage of Tr1) in accordance with the time constant C1R1, the transistor Tr1 is turned on, so that a supply voltage is applied to the amplifiers 3 and 8 of comparator type such as an operational amplifierthroughthetransistorTrl from 105 the battery 10. The reason a time constant circuit of C1R1 is provided at the base of the transistor Tr1 is to prevent error operations caused by chattering or vibration (on-off operations ofthe switch) ofthe reed switches 15 and 16 while the vehicle is travelling. 110 Further, in this embodiment, a condenser C2 and a Zener diode ZDi are provided at the emitter ofthe transistorTrl so as to obtain a constant potential s applied to comparators OPi and OP2 used as the amplifiers 3 and 8.

115 Next, a detailed description will be made hereinbe-low ofthe amplifiers 3 and 8. In Figure 3, the comparator OPt of an operational amplifier compares a reference voltage divided by two resistors R3 and R4 with a sensor signal voltaga Si developed 120 across a condenser C3; the comparator OP2 of another operational amplifier compares a reference voltage divided by two resistors R7 and R8 with a sensor signal voltage S2 developed across a condenser C4. When the sensor signal voltage Si or S2, 125 charging up the condenser C3 or C4 by the current from the battery 10, exceeds the reference voltage, the comparator Opi or OP2 outputs an UP signal or DN signal. Further, in this embodiment, the condensers C3 and C4 are also provided at the inputs ofthe 130 comparator OPt and OP2 respectively in cooperation

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with the resistors R2 and R6 so as to prevent error operations caused by chattering or vibration ofthe reed switches 15 and 16, in the same way as described for the condenser and the resisterR-i.

5 When the UP signal or DN signal is outputted, the signal is amplified by a transistor Tr2 or Tr3 to actuate the compression solenoid valve 5 or the exhaust solenoid valve 9. Therefore, as already described, the shock absorber (not shown in Figure 3 10 but shown in Figure 2) is actuated to lift or lower the vehicle according to the injection thereinto or exhaustion therefrom of a gas.

Further, in this embodiment, Zener diodes ZD2 and ZD3 are connected to the collectors of the transistors 15 Tr2 and Tr3, respectively to protect them from an excessive voltage generated from the solenoid valves 5 and 9 when these valves turned off.

As described above, according to the present invention, since a pair of mechanical switches 20 having mechanical contact points are used for detecting the level of the vehicle and, in addition, for switching the power signal to apply a supply voltage to the amplifiers, no current is passed through the amplifiers when the sensors do not detect a change 25 in level, and the vehicle level can be regulated only by applying the supply voltage to the amplifiers when the sensors detect a change in level, regardless of the on/off position ofthe ignition switch, thus preventing the battery from discharging excessively. 30 It will be understood by those skilled in the art that the foregoing description is in terms of preferred embodiments ofthe present invention wherein various changes and modifications may be made without departing from the spirit and scope of the 35 invention, as set forth in the appended claims.

Claims

1. A level regulator for an automotive vehicle 40 which comprises:

(a) a pair of mechanical switching means for respectively producing a level-up signal and a level-down signal;

(b) a level-up amplifier and a level-down amplifier 45 for respectively amplifying the level-up and level-

down signals outputted from said switching means to an UP signal and a DN signal, the supply voltage to said amplifiers being cut off when neither mechanical switching means produces its level signals; 50 (c) a pair of compression and exhaust solenoid valves respectively actuated by the UP and DN signal; and

(d) a shock absorber for lifting the vehicle when a gas is injected in response to the UP signal and for 55 lowering the vehicle when the gas is exhausted in response to the DN signal.

2. A level regulator for an automotive vehicle as claimed in claim 1, further comprising a power supply controller for applying a supply voltage to

60 said amplifiers only while said mechanical switching means detect either ofthe level signals, said power supply controller including an electric switching means for passing the supply voltage to both said amplifiers in response to either ofthe level signals, 65 said electric switching means'being connected between the battery and said amplifiers.

3. A level regulator for an automotive vehicle as claimed in claim 2, wherein said electric switching means is a transistor.

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4. A level regulator for an automotive vehicle as claimed in claim 3, wherein said power supply controller further comprises a condenserfor preventing erroneous operations caused by the chattering or vibration of said mechanical switching means, 75 said condenser being connected between the base of said transistor and ground.

5. A level regulator for an automotive vehicle as claimed in claim 3 or claim 4, wherein said power supply controller further comprises a constant vol-

80 tage circuit formed with a Zener diode and a condenser, said circuit being connected between the emitter of said transistor and ground, whereby a constant voltage is applied to said amplifiers.

6. A level regulator for an automotive vehicle as 85 claimed in claim 1, wherein each mechanical switching applies the supply voltage to the amplifier to which it is connected when it produces its level signal.

7. A level regulator for an automotive vehicle as 90 claimed in any preceding claim, wherein said amplifiers include operational amplifiers for amplifying the level signals to the UP and DN signals respectively only when the level signals exceed a predetermined voltage.

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8. A level regulatorfor an automotive vehicle as claimed in any of claims 1 to 7, wherein said pair of mechanical switching means are microswitches.

9. A level regulator for an automotive vehicle as claimed in any of claims 1 to 7, wherein said pair of

100 mechanical switching means are reed switches.

10. A level regulator for an automotive vehicle substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

Printed for Her Majesty's Stationery Office by Croydon Printing Company Limited, Croydon, Surrey, 1981.

Published by The Patent Office, 25 Southampton Buildings, London, WC2A 1AY, from which copies may be obtained.